Process of purifying oils or fats.



7 WUNITED STATES PATENT OFFICE.

HEINRICH SOHLINCK, OF LUDVVIGSHAFEN, GERMANY.

PROCESS OF PURIFYING OILS OR FATS.

SPECIFICATION forming part of Letters Patent N 0. 655,041, dated July 3,1900. Application filed October 4. 1899. Serial No. 732,531. (Nospecimens.)

To all whom it may concern.-

Be it known that I, HEINRICH SOHLINCK, a citizen of the Empire ofGermany, residing in Ludwigshafen, in the Empire of Germany, haveinvented certain new and useful Improvements in Processes of PurifyingOils, of which the following is a specification.

This invention relates to the purification of oils and fats, and moreparticularly vegetable and animal oils which are intended for hum anconsumption, the object of the invention being to remove from the oilsthe strong odor and objectionable taste which many of them in a crudestate possess and at the same time to renderthem less liable to turnrancid.

The invention consists-,broatlly, of a process of purifying oilscomprising the following steps: first, saponifying the fatty acidscontained in the oil to be purified; second, removing said saponifiedacids therefrom, and, lastly, subjecting the oil to the action ofsuperheated steam, so that the odorous matters which it contains areexpelled; and the invention consists more specifically in certain stepsmore particularly described and claimed hereinafter.

Processes having for their object the removal of the odor and taste fromoils of the class under consideration were for some time based upon asimple agitation and heating of the oil in an open vessel and subsequenttreatment with alkali. Despite the latter step oils purified by thisprocess were possessed of a tendency to readily turn rancid. Ritserth inhis Investigations Upon the Rancidt'ty of Fats, 1890, pages 46 and 48,showed that the tendency to turn rancid is the result of a directoxidation by the oxygen of the air of substances contained in the oil.This tendency is aggravated when the oil is heated in the presence ofair. Hence later processes were based upon the exclusion of air from theoil, and this necessitated the use of complicated and expensiveapparatus; but even with these processes it has been impossible toobtain from the ordinary cocoanut-oil, for example, which contains aboutfour per cent. of free fatty acids, a palatable fat not readily turningrancid. The present process is not based upon the exclusion of air fromthe oil during the process, but is based instead upon the fact that thetendency of the oils to turn rancid is due to their contained fattyacids, and

after these are neutralized and separated out the subsequent heating ofthe neutral oil does not tend to turn it rancid. The use of complicatedapparatus is avoided and a process provided by which a valuable foodproduct can be obtained from even the lowest grades of commercial oilsand fats containing a high percentage of free fatty acids andalbuininous and other odoriferous matters.

In practically carrying out the new process a quantity of the crude oiland an equal quantity of water are placed in a boiling vessel and anysuitable alkalisuch as sodium, potassium, or magnesium carbonate-addedin quantity slightly in excess of that necessary for saponifying thefree fatty acids contained in the oil. The mixture is then heated undercontinuous agitation up to the boilingpoint. The oil and the soapsolution thereby formed are then allowed to stand until they separate bygravity, which usually requires about three hours. The soap solution isthen drawn off through a faucet at the lower portion of the vessel andconducted into separating-vats, in which the contained fatty acids maybe separated from the solution by sulfuric acid or in any suitablemanner. To the oil remaining in the boiling vessel is again added anequlvalent quantity of water, the mixture again agitated and raised tothe boiling-point, and the soap solution, which is this time of lessstrength than that of the first boiling, again allowed to separate,after which it is drawn off and disposed of in like manner as the firstor in any manner desired. These washings are continued in the mannerdescribed until the washing-water runs off perfectly clear. By thiscontinued washing the fatty acids, which are neutralizedby the alkaliand form part of the soap solution, are removed from the oil. Theso-purified oil is then treated for the removal of the.odors stillcontained-in the same by subjecting it to the action of superheatedsteam, in a wroughtiron apparatus provided with a cap and cooler, up toa temperature of from 180 to 200 centigrade, until a test taken from thestill has neither smell nor taste, which, ac cording to the kind andquality of the oil, takes from three to six hours. The volatile portionswhich pass off with the superheated steam are condensed in the coolerand float as a thin fatty film on the water in the receiving-vat, fromwhich they can be readily ladled off from time to time.

Having thus described my invention, 1 claim as new and desire to secureby Letters Patent 1. The herein-described process of purifying vegetableand animal oils and fats, which consists in the following steps: first,saponifying the free fatty acids contained in the oil, second,separating the soap solution thereby formed from the oil, and lastlysubjecting the aciclless oil to the action of superheated steam fordeodorizing the same, substantially as set forth. 7

2. The herein-described process of purifying vegetable and animal oilsand fats, which consists in the following steps: first, saponi fying thefree fatty acids contained in the oil by a suitable alkali, second,separating the soap solution from the oil, third, subjecting theremaining oil to successive washing operations, and lastly, subjectingthe so-washed acidless oil to the action of superheated steam, so as toremove the volatile ingredients contained in the same, substantially asset forth. In testimony that I claim the foregoing as my invention Ihave signed my name in presence of two subscribing witnesses.

HEINRICH SCHLINOK. Witnesses:

KARL FI'JRNITZ, JAKoB MUNZER.

